Electric vehicles already offer car designers much greater freedom than internal combustion vehicles, eliminating the need to find space for the rigid shape of an engine, its transmission and its ancillaries.

That's not to say electric vehicle packaging can't be improved though, and Mitsubishi is aiming to do just that with its prototype electric drive system.

The new motor should not only offer improved energy efficiency, but due to its design can liberate greater space within the vehicle body for useful pursuits like interior and trunk room.

At 60 kW (80 horsepower) the motor's output is roughly on par with existing motors and with the integrated inverter the drive system as a whole is similar in size to an existing electric motor, meaning packaging is simple.

Parallel cooling ducts for the motor and inverter sit within the unit, and Mitsubishi says they offer stable cooling even with a low-power pump.

Part of the importance behind reducing the size of the motor and inverter is that battery technology still lags behind actual drive technology in many ways, and it's currently easier to reduce the size of drive system components than it is the large, heavy battery pack.

By offering more space within the vehicle's drivetrain, a larger battery pack can feasibly be used without sacrificing overall vehicle weight or interior volume.

Mitsubishi says it holds 94 patents for the new drive system in Japan and a further 29 abroad. There's no indication on how close the system is to production, but it's fair to say we'll probably see motors very much like it in Mitsubishi's next generation of electric vehicles.

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